dtrace(1): add -d flag to dump D script post-dt_sugar

By specifying the -d flag, libdtrace will dump the D script after it has
applied syntactical sugar transformations (e.g if/else). This is useful
for both understanding what dt_sugar does, as well as debugging it.

Reviewed by:	markj
Approved by:	markj (mentor)
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D38732

2 files changed, 13 insertions, 6 deletions

diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_cc.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_cc.c
index e63771c91e08..f3fda4af834e 100644
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_cc.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_cc.c
@@ -2478,10 +2478,7 @@ dt_compile(dtrace_hdl_t *dtp, int context, dtrace_probespec_t pspec, void *arg,
 		    "not referenced)\n", yypcb->pcb_sargv[argc - 1], argc - 1);
 	}
 
-	/*
-	 * Perform sugar transformations (for "if" / "else") and replace the
-	 * existing clause chain with the new one.
-	 */
+	/* Perform sugar transformations. */
 	if (context == DT_CTX_DPROG) {
 		dt_node_t *dnp, *next_dnp;
 		dt_node_t *new_list = NULL;
@@ -2492,8 +2489,17 @@ dt_compile(dtrace_hdl_t *dtp, int context, dtrace_probespec_t pspec, void *arg,
 			next_dnp = dnp->dn_list;
 			dnp->dn_list = NULL;
 
-			if (dnp->dn_kind == DT_NODE_CLAUSE)
+			if (dnp->dn_kind == DT_NODE_CLAUSE) {
 				dnp = dt_compile_sugar(dtp, dnp);
+				if (cflags & DTRACE_C_SUGAR) {
+					dt_node_t *p;
+
+					dt_printd(dnp, stdout, 0);
+					for (p = dnp->dn_list; p != NULL;
+					    p = p->dn_list)
+						dt_printd(p, stdout, 0);
+				}
+			}
 			/* append node to the new list */
 			new_list = dt_node_link(new_list, dnp);
 		}
diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dtrace.h b/cddl/contrib/opensolaris/lib/libdtrace/common/dtrace.h
index f0bc83a7fc7b..af0213695f32 100644
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dtrace.h
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dtrace.h
@@ -119,10 +119,11 @@ typedef struct dtrace_proginfo {
 #define	DTRACE_C_PSPEC	0x0080	/* Interpret ambiguous specifiers as probes */
 #define	DTRACE_C_ETAGS	0x0100	/* Prefix error messages with error tags */
 #define	DTRACE_C_ARGREF	0x0200	/* Do not require all macro args to be used */
+#define	DTRACE_C_SUGAR	0x0400	/* Dump D script post-dt_sugar */
 #define	DTRACE_C_DEFARG	0x0800	/* Use 0/"" as value for unspecified args */
 #define	DTRACE_C_NOLIBS	0x1000	/* Do not process D system libraries */
 #define	DTRACE_C_CTL	0x2000	/* Only process control directives */
-#define	DTRACE_C_MASK	0x3bff	/* mask of all valid flags to dtrace_*compile */
+#define	DTRACE_C_MASK	0x3fff	/* mask of all valid flags to dtrace_*compile */
 
 extern dtrace_prog_t *dtrace_program_strcompile(dtrace_hdl_t *,
     const char *, dtrace_probespec_t, uint_t, int, char *const []);